code: def stacked_example():
      """Dictionary of stacked arrays, i.e. stacked form. Corresponds to unstacked_example."""
      return {"a": np.array([[1], [2]]), "b": np.array([[3], [4]])}
  
file_path: maze/maze/test/train/utils/test_train_utils.py
imports: import numpy
  import torch
  from maze.perception.perception_utils import convert_to_torch
  from maze.train.utils.train_utils import unstack_numpy_list_dict, stack_numpy_dict_list, stack_torch_dict_list
label_desc: Use image node_id 1 for calling a global function with example usage: stacked_example() and returns: dict